The central purpose of this research is to test the efficacy of a collagen based tubular prosthesis to promote axonal regeneration in the peripheral nervous system in vivo. The prosthesis is nontoxic and biodegradable and is fabricated from natural connective tissue components. During Phase I we will continue our studies in rodents, while Phase II would concentrate on non- human primates and potential human clinical trails. Using both anatomic and physiologic techniques, we will quantify and directly compare current standard nerve repair procedures with the new tubular prosthesis described in this grant proposal. Specific Aim I will focus on the production and quality control testing of collagen based nerve guides. Specific Aims II through IV will involve biological testing of the nerve guides and a critical comparison of peripheral nerve repair using standard clinical nerve microsuture and grafting procedures vs entubulation repair with the collagen based prosthesis. Such quantitative comparisons have direct clinical relevance to human peripheral nerve repair. The large scale commercial application of an effective nerve repair prosthesis can be appreciated from estimates that currently more than 200,000 nerve regeneration procedures are performed in the U.S. per year.